What your baby’s poo tells you. 


Today we’re going to don our Hazmat suits and take a journey through the different stages of baby poo. As with all of us, a baby’s poo can reveal the story of their overall health and well-being.

We’ll start at the very beginning.

In utero, a baby swallows the amniotic fluid. The fluid passes through the gut and becomes the baby’s first poo, known as meconium. This is black, sticky, sterile, has no smell and usually is passed within 24 hours post birth – it is important that the baby has passed meconium as we then know the anus is open (some babies have what is called an imperforate anus, which means the baby has improperly developed anus and cannot pass a poo).

If for different reasons, a baby who is distressed during pregnancy or labour the baby can pass the meconium into the amniotic sac where it becomes  an irritant to the baby’s lungs. If inhaled, it can cause pneumonia.

Once the baby starts breastfeeding, its poo changes from a dark green, transitional poo to a bright yellow. If the baby is drinking formula, the poo is usually a dark green, sticky substance.

Exclusively breastfed babies can poo before, during and after every feed. They are rarely constipated as the baby absorbs all the waste product leaving little to excrete. This is the reason breastfed babies can sometimes go a week to 15 days without pooing. It’s nothing to worry about. If the baby is passing wind and otherwise well, no treatment is required. And don’t be concerned if  your baby grimaces and strains during a poop. Even though they’re passing soft stools, their little bottoms aren’t strong or coordinated enough for easy elimination. The odd grunt is to be expected.

The best way to assist a baby to poo is to continue with feeding. Babies have what is called oro anal reflex. When a baby sucks it stimulates the rectum to evacuate the bowel. This usually happens when a baby is feeding and the baby will often pass wind or have a poo. The colour of newborn poo can change quite often, along with its texture and even the smell.

If your baby’s poo appears to be red from blood it may be due to a cow’s milk protein allergy. A black poo may indicate bleeding in the upper gut whereas a white poo may highlight liver issues.

It’s important to seek medical advice if you are concerned. Take the contents of the nappy, or a clearly defined photo to show your doctor. Never give a baby any medicine unless your doctor prescribes it.

Most babies will go through about 6 to 8 nappies a day so you’ll be spending a more time than you ever imagined looking at poo. It’s all part of the joy of a newborn, especially as a healthy poo is a great sign of a healthy baby.

Different poo

Day 1 – the baby should pass meconium, a black, sticky sterile poo. Unlike later poo, meconium is composed of materials ingested during the time the infant spends in the uterus…intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile and water

Day 2 – meconium will still be passed in the early hours of day 2.

Day 3 – as milk starts to flow through the baby’s gut (breast milk or formula) the black meconium changes to a dark green poo which we call a transitional stool.

Day 4 – the poo can start to change to yellow as the breast milk is starting to be established. It may be dark green if the baby is fully formular fed.

Day 5 – breastfed poo is more liquid than formed and a the poo can be really runny. So prepare for some “poonarmi’s”

Remember when a baby is milk, exclusively breastfed they will not get constipated. A breastfed baby can go over 18 days without a poo…but when the baby finally does have a poo…it is massive.


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